The present invention relates to a method for supplying water to a treatment liquid when the levels of treatment liquids in treatment tanks of a photo-developing apparatus fall due to evaporation, and a photo-developing apparatus employing such a water supplying method.
In recent years, photo-developing apparatuses have been widely in use which automatically develop a photosensitive material such as a printing paper and a film by passing it through treatment tanks containing treatment liquids. In such photo-developing apparatuses, when the concentrations of the treatment liquids become dense due to the evaporation thereof during the operation, water is put into the treatment tanks to keep the concentrations of the treatment liquids at proper values (see Japanese Unexamined Patent Publications Nos. 1-281446, 3-249646, 3-280042). In other words, in order to keep the concentrations of the treatment liquids at proper values while the apparatus is in operation, the first publication No. 1-281446 discloses a technique for supplying water based on an actual amount of photosensitive material to be developed; the second publication No. 3-249646 discloses a technique for supplying treatment liquids after water is supplied; and the third publication No. 3-280042 discloses a technique for supplying water based on atmospheric temperature/humidity.
The evaporation of the treatment liquids in the photo-developing apparatus occurs not only when the photo-developing apparatus is in operation, but also after the operation is stopped, regardless of whether or not the developing operation is being performed. Accordingly, the developing operation may be started with the dense treatment liquids when the photo-developing apparatus is restarted after being suspended for a predetermined time or longer. Since only the concentrations of the treatment liquids during the operation are taken into consideration with the prior art techniques, a sufficient development stability may not be ensured at all points of time during the operation of the photo-developing apparatus including an operation starting time.